Photo-biochemical transformation of dissolved organic matter on the surface of the coastal East Antarctic ice sheet

Antony, Runa; Willoughby, Amanda S.; Grannas, A. M.; Catanzano, V.; Sleighter, Rachel L.; Thamban, Meloth; Hatcher, Patrick G.

doi:10.1007/s10533-018-0516-0

Cited by 29 publications

(32 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is likely that in the UV+PAR treatment, these opposing processes (the degradation and formation of humic-like DOM) are occurring simultaneously, with formation driven by PAR representing the dominant process. This contrasts with the findings of Antony et al, (2018); however, may simply represent the difference in DOM composition between surface ice of the GrIS and snow in Antarctica. Although DOC concentrations were consistent across light treatments, we have demonstrated that surface ice DOM undergoes structural and compositional changes following exposure to UV and PAR.…”

Section: Surface Ice Domcontrasting

confidence: 97%

“…Biodegradation incubations revealed that certain components of glacier algal pigment may be transformed by the heterotrophic bacterial community. Consistent with previous studies, SUVA254 and SUVA365 increased across incubations, concomitant with decreasing contributions of proteinaceous fluorescence and suggestive of preferential consumption of LMW aliphatic DOM by bacterial communities (Antony et al, 2018;Hansen et al, 2016;Kirchman, 2003). Most notably, reduced absorption associated with purpurogallin carboxylic acid and gallic acid glycoside indicates that these compounds may comprise a proportion of the bioavailable substrates consumed by the bacterial community.…”

Section: Glacier Algal Phenolic Pigmentsupporting

confidence: 88%

“…Thus far, investigations into DOM cycling in glacial environments have revealed that photodegradation produces a slight increase in bioavailable DOM in Antarctic snow samples (Antony et al, 2018). However, DOM biodegradation was found to produce photoreactive compounds highlighting the interlinked nature of these two processes (Antony et al, 2017(Antony et al, , 2018. Here, we hypothesise that photodegradation may alter the composition and bioavailability of organic carbon to heterotrophic bacterial communities, subsequently impacting biodegradation pathways in surface ice.…”

Section: Introductionmentioning

confidence: 74%

“…the susceptibility of glacier algal secondary phenolic pigment to photodegradation (given its maximum absorbance in UV-B wavelengths) and its bioavailability to heterotrophic bacteria; and the components of surface ice DOM that are degraded by heterotrophic bacteria. Thus far, investigations into DOM cycling in glacial environments have revealed that photodegradation produces a slight increase in bioavailable DOM in Antarctic snow samples (Antony et al, 2018). However, DOM biodegradation was found to produce photoreactive compounds highlighting the interlinked nature of these two processes (Antony et al, 2017(Antony et al, , 2018.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Photodegradation and biodegradation of dissolved organic matter on the surface of the Greenland Ice Sheet

Nicholes

Williamson

Tranter

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. The surface (supraglacial) environment of the Greenland Ice Sheet (GrIS) is an active site for the storage, transformation and transport of carbon, which is driven by extremely high levels of solar radiation throughout the ablation season. Within the south west of the GrIS, blooms of Streptophyte micro-algae (hereafter glacier algae) at abundances of ~ 105 cell mL−1 dominate primary production in the surface ice and provide dissolved organic matter (DOM) to the heterotrophic bacterial community. Glacier algae contain photoprotective secondary phenolic pigment that comprises a large proportion of the cell (~ 4 % of the dry weight) and could represent a substantial, additional carbon source for the heterotrophic community. The transformation and degradation of DOM by solar radiation (photodegradation) and heterotrophic communities (biodegradation) represent two crucial controls on DOM composition and quantity; however, the influence of these processes within the surface ice is yet to be constrained. This study therefore assessed responses in the composition and quantity of two carbon sources (glacier algae secondary pigment and surface ice DOM) following exposure to UV, PAR, UV+PAR (photodegradation) and subsequent incubation with bacterial communities isolated from the ambient environment (biodegradation). Our results indicate that exposure to predominantly UV radiation altered the composition of glacier algal pigment and surface ice DOM; however, the quantity of DOM remained constant. Biodegradation caused the greatest changes to both DOM composition and quantity, particularly in surface ice DOM. Secondary pigment extracted from glacier algae was not a highly bioavailable source of carbon and did not support significant growth of surface ice heterotrophic bacterial communities. Conversely, low molecular weight compounds in surface ice DOM were rapidly utilised by heterotrophic bacteria supporting between a 3 and 9-fold increase in bacterial abundance over a 30-day incubation. We found that photodegradation of glacier algal pigment and surface ice DOM did not influence heterotrophic consumption. Photodegradation and biodegradation of DOM in the surface ice habitat are likely intimately linked and act as fundamental controls on the composition and quantity of DOM exported to downstream environments.

show abstract

Section: Surface Ice Domcontrasting

confidence: 97%

Section: Glacier Algal Phenolic Pigmentsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photodegradation and biodegradation of dissolved organic matter on the surface of the Greenland Ice Sheet

Nicholes

Williamson

Tranter

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…The dissolved organic matter (DOM) transformations by supraglacial microbes revealed that both autochthonous and allochthonous DOM is highly bioavailable and is transformed by resident microbial communities through parallel processes of degradation and synthesis . The biogeochemistry of DOM is highly complex and intimately connected with microbial and photochemical processes operating individually or in combination (Antony et al, 2018).…”

Section: Glaciochemical Processes and Biogeochemistrymentioning

confidence: 99%

Palaeoclimatic records from Antarctica and Southern Ocean: A review of Indian contributions

Thamban

2020

Episodes

Self Cite

View full text Add to dashboard Cite

Polar regions are highly sensitive to climate change and are crucial for regulating the Earth's climate. While the past climatic changes were forced differently than the ongoing and future anthropogenic changes, such periods may provide insights into potential future climate impacts and ecosystem feedbacks, especially over centennial-to-millennial timescales that are often not covered by climate model simulations. As part of the initiatives to better understand the polar climate system and its global linkages, Indian scientists have been undertaking palaeoclimatic studies, mainly from the Antarctica, its margins and the surrounding Southern Ocean. Antarctic palaeoclimate records come primarily from proxy records of ice cores or marine and lake sediment cores. Among ice core records, the Indian contributions have been focussing on a network of annually resolved shallow depth ice cores to reconstruct the Antarctic climate variability and its regional and global climatic teleconnections, especially during the past few centuries. Compared to this, the Antarctic lake sediment records have focussed on long-term climate variability, especially during the late Quaternary. Recently, as part of the collaborative initiatives under the International Ocean Discovery Program, Indian scientists have been studying longer sedimentary records from the Antarctic continental margin that offer opportunity to study the evolution and dynamics of the Antarctic ice sheets since their formation during the Cenozoic.

show abstract

Biolability of Fresh and Photodegraded Pyrogenic Dissolved Organic Matter from Laboratory-Prepared Chars

Bostick

Zimmerman

Goranov

et al. 2020

Preprint

View full text Add to dashboard Cite

Pyrogenic dissolved organic matter (pyDOM) is known to be an important biogeochemical constituent of aquatic ecosystems and the carbon cycle. While recent studies have examined how pyDOM production, composition, and photolability varies with parent pyrogenic solid material type, we lack an understanding of potential microbial mineralization and transformation of pyDOM in the biogeosphere. Thus, leachates of oak, charred at 400 °C and 650 °C, as well as their photodegraded counterparts were incubated with a soil-extracted microbial consortium over 96 days. During the incubation, significantly more carbon was biomineralized from the lower versus higher temperature char leachate (45% vs. 37% lost, respectively). Further, the photodegraded leachates were biomineralized to significantly greater extents than their fresh non-photodegraded counterparts. Kinetic modeling identified the mineralizable pyDOC fractions to have half-lives of 9-13 days. Proton nuclear magnetic resonance spectroscopy indicated that the majority of this loss could be attributed to low molecular weight constituents of pyDOM (i.e., simple alcohols and acids). Further, the quantification of benzenepolycarboxylic acid (BPCA) molecular markers indicated that condensed aromatic compounds in pyDOM were biomineralized to much lesser extents (4.4% and 10.1% decrease in yields of ΣBPCA-C over 66 days from 400 °C and 650 °C oak pyDOM, respectively), but most of this loss could be attributed to the biomineralization of smaller condensed clusters (four aromatic rings or less). These results highlight the contrasting bioavailability of different portions of pyDOM, and the need to examine both to evaluate its role in soil or aquatic heterotrophy and its environmental fate in the hydrogeosphere.Plain Language Summary Given the recent changes in wildfire frequency and intensity in many areas of the globe, it is important to understand the fate of charred biomass in soils. As char is degraded in soils, it dissolves into porewaters, from where it then moves through the soil into rivers and ultimately to the ocean. The current study strives to understand how microbial decomposition destroys or alters fire-derived dissolved organic carbon. To accomplish this, two chars were leached in water and were incubated with soil microbes. This study found that about half of the carbon in these leachates could be readily decomposed, that is, converted back to carbon dioxide (with some variation with char leachate type). However, the other half of the leachate was resistant to microbial utilization. As such, one could expect that this remaining portion might be transported by rivers to the ocean, potentially influencing aquatic ecology and global carbon cycling.

show abstract

Photo-biochemical transformation of dissolved organic matter on the surface of the coastal East Antarctic ice sheet

Cited by 29 publications

References 70 publications

Photodegradation and biodegradation of dissolved organic matter on the surface of the Greenland Ice Sheet

Photodegradation and biodegradation of dissolved organic matter on the surface of the Greenland Ice Sheet

Palaeoclimatic records from Antarctica and Southern Ocean: A review of Indian contributions

Biolability of Fresh and Photodegraded Pyrogenic Dissolved Organic Matter from Laboratory-Prepared Chars

Contact Info

Product

Resources

About